This invention relates to D.C. stepper motors equipped with a permanent magnet rotor and electronic commutation device in general and more particularly to an improved motor of this type.
D.C. stepper motors in which the individual winding circuits can be addressed successively via a selector circuit and the current flowing in the winding circuits can be regulated to a constant value by means of a current regulator are known.
If such a motor is to be stopped in a given position, the commutation sequence is interrupted while the last prevailing signal is continued. The permanent magnet rotor then positions itself in alignment with the current-carrying winding axis. In so doing, the rotor comes to rest at the desired position only after protracted oscillations. After the rotor is positioned, a considerable power loss in the motor is converted into heat, although the motor current is kept constant by the current regulator.